I agree with what Mark had mentioned and actually just used this tactic last month! I was being a bit of a softy and hesitant to raise rent on a unit for too long. My tenants were paying $100 under market rent. My initial thought was to raise rent $25. I ended up having a conversation with the tenants and making them aware they were paying $100 less than market rent. Say said, " we know". I said , " Im not going to raise your rent $100.00 on you, but what type of increase could you do?." They said," we could do $50 a month" . So like Mark said you might be surprised. If they didn't come back that high it would of at least started the negotiation. This was not something I thought of but was advise given to me. I will now raise rent annually to avoid the whole kit and kabootle.
